Timer



April 11, 1939. .1. ARMSTRONG 2,153,540

' TIMER Filed Dec. 21, 1936 2 Sheets-Sheet l INVENTOR Lep/mra LIA/7776 from ATTORNEY April 11, 1939. 1.. J. ARMSTRONG 2,153,540

TIMER Filed Dec. 21, 1956 2 Sheets-Sheet 2 #55 INVENTOR 76 a 0 i jgddauz /frmafrong ATTORNEY Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE TIlVlER Application December 21, 1936, Serial No. 116,984

9 Claims.

This invention relates to timers for internal combustion engines, and aims to provide certain improvements therein. More particularly it relates to a timer of the positively actuated type '5 disclosed in my Patent No. 1,914,231.

In the timer of said patent I provide a pair of movable arms which are each pivoted at one end, and which carry at their opposite ends a pair of contacts or breaker points, said arms each being disposed between a pair of cams which are of such configuration that upon rotation thereof, a back and forth motion is imparted to the arms, which in turn causes the movable breaker points to make and break contact With' a set of stationary breaker points mounted independently thereof.

Timers of this type are designed particularly for use in high-number or multiple cylinder internal combustion engines, although they may be used to advantage in eight or less cylinder engines which are equipped with dual ignition.

One of the objects of the present invention is to provide dampeners for the free ends of the spring arms carrying the movable breaker points, so as to prevent independent vibration of the arms and consequent bounce or skip of the breaker points on making contact, when the timer is running at high speed.

Another object of the invention is to provide a more exact make and break of contact between the movable breaker points and the stationary breaker points, by tensioning slightly the spring arms carrying the movable breaker points to resist lateral displacement, and then forcing the arm and breaker points back and forth positively against the tension of the arms.

Another object of the invention is to provide an improved retaining box for the cam riding blocks, which is of simple design, and adapted to be easily slipped into and out of operative position.

These, and other objects of the invention which will be made apparent as the description progresses, are illustrated in the accompanying drawings, wherein the preferred embodiment of the invention is shown, and wherein- Figure 1 is a plan view illustrating the timer of the present invention.

Fig. 2 is a view in front elevation, partly in section, of the timer shown in Fig. 1, the sectional view being taken on the line 2-2 of Fig. 1, and parts being broken away to show underlying structure.

Figs. 3 and 4 show details of the spring arm construction for mounting the cam riding block boxes.

Figs. 5 and 6 show details of structure of the cam riding blocks and boxes, Fig. 5 being a side elevation and Fig. 6 being a front elevation.

Figs. 7, 8 and 9 show details of construction of the vibration dampeners for the movable arms, Fig. '7 being a fragmentary, top plan of the arm and end mounting; Fig. 8 being a plan of the end mounting; and Fig. 9 being a view in front elevation of the end mounting of Fig. 8.

Figs. 10 to 12 inclusive, and 13 to 15 inclusive, show two modifications of the vibration dampeners and end mountings.

Fig. 16 is a plan view of one of the arms, showing its initial shape before assembly in the timer.

By referring to the drawings it will be seen that the lower end of a timer shaft 5 is journalled in a bearing block 6, which is fitted into the lower end of a timer casing 1. At its upper end the casing I is of enlarged diameter and cup-shaped, and has its open upper end closed by a fiat metal plate 8, on which is mounted most of the timer mechanism, the timer shaft extending through the plate through a hole formed therein. As will be seen in Fig. 2, the plate 8 seats on shoulders 9 formed in the timer casing 1. A bearing for the upper end of the timer shaft 5 is shown at IU, said bearing being provided with a bushing H, having an annular flange l2 which seats on a shoulder [3 formed in the plate-8.

Secured to the shaft 5, above the plate 8, is a gear l4, having above it and integrally formed therewith a cam l5, said gear and cam being adapted for rotation with said timer shaft 5, and being held in position thereon by a nut l6 screwed on the threaded upper end of the shaft. Laterally spaced from the shaft 5 are stub shafts l1 and [8, the lower ends of which are of reduced diameter and screw-threaded, protruding through holes formed in the plate 8, each of said stub shafts being held in position on the plate by an abutment 20 which bears against the upper face of the plate, and by a washer and nut 21 which bear against the under face of the plate.

Mounted for rotation on the stub shaft I1 is an integrally formed gear 24 and cam 25, the gear and cam being provided with a bushing 26 and being held in position on the shaft by a washer 21 and cotter pin 28. Mounted similarly for rotation on the stub shaft I8 is a gear 30 formed integrally with a cam 3 I, being held in position on the shaft l8 by a washer 32 and cotter pin 33. The two gears 24 and 30, as shown in Fig. 1, mesh with the central driving gear l4 and are driven thereby.

Disposed between the cams l5 and 25 is an arm 35, which is preferably a spring arm, and which, according to the present invention, is made of two elongated spring-steel blades, which, when mounted in operative position (as shown in Fig. 1) assume a straight line shape, being held in juxtaposition, face to face. The precise construction of the arm will be referred to hereafter in greater detail. Similarly disposed between the cams l5 and 3| is an arm 36 of like construction, the twoarms 35 and 36 being here shown as formed of continuous strips of spring steel which are bent around a stud post 40 to, form a V, and which are clamped in position thereagainst by a crescent-shaped clamping member 4| and screw 42. The opposite ends of the arms 35, 36 are mounted in slots 44 formed in studs 45, the ends of the arms being flared outwardly to bear against the inner side faces of the slots, and being held thereagainst by spring pressure. The studs 45 are provided with slotted base members 46 which are held in position on the base plate 8 by a machine screw 41 and a short stud 48, the stud serving to prevent lateral movement but permitting longitudinal adjustment. Near the center of each of the arms 35, 36, and disposed on the opposite faces thereof, is mounted a pair of boxes 50, 5|, which serve as retainers for fiber riding blocks 53 against which the faces of cams I5, 25 and 3| bear. The details of construction of the boxes will be hereinafter more fully described.

It will be understood that the cams I5, 25 and 3| are of such configuration that their cam bearing faces are always in contact with the fiber riding blocks 53 on the arms 35, 36, and that upon rotation of the timer shaft and cams through the medium of gears I4, 24 and 30, cams l5 and 25 will act to move arm 35 back and forth positively, and similarly cams l5 and 3| will act to move arm 36 back and. forth positively.

Each of the arms 35 and 36 is provided with a pair of oppositely-disposed contact members or breaker points 55, which are preferably welded thereon and movable therewith, and which are adapted to make contact with a set of stationary contacts or breaker points 56 between which the movable breaker points 55 are disposed. The stationary breaker points 56 are mounted in supports 60 which are insulated from the base plate 6, and from each other, by suitable insulating material 6|. (No claim is made herein to the separate supports. These are claimed in my pending application No. 92,128, filed July 23, 1936.) Each of said supports is split, as shown in Figs. 1 and 2, and has at its upper end a threaded aperture into which is screwed the threaded end of breaker points 56, said breaker points having nuts 63 formed integrally therewith which facilitate manual adjustment of the breaker points by screwing them into or out of the supports 60, as may be desired. The supports 60, as previously mentioned, are split, and have cap screws 64 extending therethrough, which, when screwed up tightly, lock the threaded breaker points in position. As best seen in Fig. 2, each of the supports 66 is held in position on the plate 8 by a screw 66 extending upwardly through the base of a terminal member 68 which is insulated from the plate by insulating material the screw also being insulated from the plate by a fiber ferrule not here shown. The terminal member 66, as shown, consists of a flat base and a lug H which projects downwardly at an angle to the base, the lug being provided with a threaded aperture 12 to facilitate attachment of a lead from the primary coil of an internal combustion engine.

Referring now more particularly to the arms 35, 36, it will first be noted that each of the arms consists of two, separate, elongated, springsteel blades 15, 16, which, when assembled in the timer, assume a straight line configuration. Before assembly in the timer, the blades have a configuration similar to that shown in Fig. 16, wherein it will be seen that each blade is bowed outwardly between the breaker point 55 and the pivotal end of the arm 11 (which is intended to be clamped against the stud post 40). From the breaker point 55 to the opposite end 18 of the arm, it will be noted that each blade is bent outwardly at an angle, and that the extreme ends 18 are flared outwardly at a greater angle, the flared ends being intended to be fitted into the slots 44 in studs 45. With an initial configuration as thus described, it will be apparent that when the blades are pressed together and assembled in the timer in a straight line position, each blade, and accordingly each arm, will be under tension, and will tend to resist lateral displacement. Midway of the bowed portion of each 25 blade, at the top and bottom edges thereof, is a pair of outwardly extended flanges 9B, which are formed integrally with the blades, said flanges being best seen in Figs. 3, 4 and 16, and being of a width, length and thickness to accommodate a pair of retaining boxes 5|] for the fiber riding blocks 53, which are intended to be mounted thereon.

Referring now to Figs. 5 and 6 which show details of the retainer boxes 50 for the fiber riding blocks, it will first be noted that the boxes are of rectangular shape, being formed from a rectangular piece of sheet metal. It will also be noted that the boxes are formed with transverse slots cut in their side edges, parallel to the bottom edge, to a depth corresponding to the width of the side flanges 8| of the box, which are turned inwardly. The slots also are located at a point below the top and above the bottom edges of the metal sheet (from which the box is formed) which corresponds to the width desired for the top and bottom flanges 62, 83 of the box. Each of the four edges of the metal sheet are turned inwardly at right angles to the base, to provide the four sides of the box, the top and bottom flanges each having lugs 64 which are turned upwardly and inwardly to provide hooks. When mounting the boxes on the arms 35, 36, the hooks 84 are slipped over the flanges 90 and then pressed inwardly to embrace the flanges firmly, being held thereby in position on the arms. From Fig. 16 it will be observed that the boxes and riding blocks are mounted on the arms at the center of the outwardly bowed portion. When assembled in the timer, the bow will then normally tend to force the riding blocks outwardly against the cam bearing faces, and in this way to make contact at all times, compensating for wear of the riding blocks during use.

In order to prevent vibration of the arms 35, 36, and consequent bounce or skip of the breaker points on making contact, particularly when the timer is running at high speed, I provide dampeners for the movable ends of the arms carrying the movable breaker points 55. Previously, as seen in my Patent No. 1,914,231, the movable breaker points 55 were mounted on the free outer ends of the arms, and were capable of lateral movement by independent vibratory motion of the arm, the movement of the arms being only partially restrained. By the present invention I provide longer arms 35, 36, and mount the movable breaker points 55 inwardly of the ends thereof, the extreme outer ends 18 of the arms being mounted in slots 44 formed in studs 45, and being held therein under spring pressure by the outwardly flared ends of the spring arms which bear against the inner side faces of the slots. In this manner the arms are restrained in their movement, being incapable of independent vibratory motion. Yet, with this type of dampener, or end mounting for the arm, the arm is still capable of being flexed, and upon rotation of the cams l and 3| the arm 35, intermediate its ends, will move back and forth and bring the movable breaker points 55 into and out of contact with the stationary breaker points. In moving the arms back and forth, the cams must overcome the tension in the arms, previously described, which tends to maintain the arms in a straight line position. In this way a strictly positive back and forth motion of the arms and movable breaker points is obtained, the spring arm itself not having any independent motion, but deriving its motion entirely from the cams. Also, in this way a more exact make and break of contact between the points is assured.

In Figs. to 12, and 13 to 15, two modified forms of dampeners and end mountings are In the first modification the ends of the rqomhowni arm blades are formed with hook-shaped portions 96 (Fig. 10) which press outwardly against a pair of upstanding studs 91. In the second modification (Fig. 13) the ends of the arm blades are curled around a pair of studs 98.

From the foregoing it will be apparent that the essential characteristics of the dampeners are to prevent lateral swing of the arms at their nonpivotal ends, and to permit the arms to be displaced laterally at the movable breaker points in order to make contact with the stationary breaker points. It will be obvious that other restraining means, or dampeners, may be provided, difiering from those herein shown, which will possess these essential characteristics.

Another feature of the present invention resides in so constructing the timer as to provide a sufficient amount of dwell of the breaker points, it being understood that the points should remain in contact long enough to permit of saturation of the primary coil; otherwise, the current induced in the secondary coil will be of correspondingly decreased strength. In order to provide sufficient dwell, the timer is so constructed that contact of the movable breaker points 55 with the stationary breaker points 56 is made before the high point on the actuating cam 31 bears against the fiber riding block 53, and the contact of the points is continued until a corresponding point on the opposite side of the high point of the actuating cam bears against the riding block. It will of course be understood that when contact between a set of points is made, the movable breaker point 55 will cease to move, but as the cam 3| continues to force the arm 35 laterally in the same direction, the arm will flex above the breaker point 55.

Still another advantage which accrues from the present construction of timer, is in providing a greater pressure at the breaker points tending to hold them in intimate contact. When contact is made, as previously described, before the high point on the actuating cam bears against the riding block, the spring arm 35 flexes as the cam continues to force the arm laterally. At the same time, the outer end of the arm which is mounted in the vibration dampener and restrained from lateral movement, resists a reactionary force in the opposite direction which is set up as the arm tends to pivot about the breaker points. The result is that the portion of the arm above the breaker point, which is intermediate the riding block 53 and breaker point 55, flexes in the direction of movement of the arm, and the portion of the arm which is below the breaker point, intermediate the breaker point and dampener, flexes in the opposite direction. Both sections of the arm in turn exert reactionary forces which force the points together under considerable spring pressure.

In operation, when the timer is used in an automobile gasoline engine, a lead from a primary coil of an induction circuit will be connected to each of the downwardly extended lugs H at the base of the supports for the stationary breaker points 55 (Fig. 2), the primary coil or coils being connected to a suitable source of electrical energy (not here shown), such as the usual storage battery. Upon rotation of the timer shaft 5, and in turn the cams i5, 25 and 3| through the medium of gears I4, 24 and 30, the movable breaker points 55 will successively be brought into contact with the adjacent stationary breaker point. When contact is made, the circuit is completed, and electric current flows from the storage battery, through the primary coil to the support 60, and then through the arms 35 to the end mounting 45, where it is grounded to the plate 8 and easing 1. When the contact between the points is broken, this in turn induces a current in the secondary coil which causes a jump spark across the spark plug gaps, in a manner well understood.

WhileI have shown and described the preferred embodiment of my invention, it will be understood that various changes may be made therein without departing from the spirit of the invention, or from the scope of the appended claims.

What I claim is:

1. A timer comprising an arm having a pair of movable breaker points thereon disposed opposite one another, a pair of spaced apart stationary breaker points adjacent said movable breaker points, means for moving said arm to bring said movable breaker points alternately into and out of contact with said stationary breaker points, and a vibration dampener for said arm for resisting movement thereof laterally in opposite directions for dampening any independent vibratory motion thereof.

2. A timer according to claim 1, wherein said vibration dampener comprises resilient means and a pair of fixed stops co-acting with the free end of said arm, the resilient means being on one of said parts for engagement with the other.

3. A timer comprising two rotatable cams, an arm disposed between the cams and having thereon a pair of movable breaker points dis.- posed opposite one another, the arm being tensioned throughout its length to resist but not prevent lateral displacement in opposite directions, the cams having cam surfaces which engage opposite sides of the arm to positively move the arm back and forth against the tension of the arm, and a pair of spaced apart stationary breaker points adjacent said movable breaker points which are adapted to be contacted a1- ternately by said movable breaker points.

4. A timer according to claim 3, in which tensioning of the arm is accomplished by the arm comprising two, elongated, spring blades, which normally are bowed outwardly with relation to one another, and which when assembled in the timer are pressed together to assume a straight line position, face to face.

5. A timer comprising two rotatable cams, an arm disposed between said cams, the arm being pivoted at one end and having a pair of movable breaker points mounted thereon inwardly of its opposite end, said arm being composed of two elongated, spring blades which normally are bowed outwardly with relation to one another intermediate the pivotal end of the arm and the movable breaker points, and are flared outwardly from the breaker points to the opposite end of the arm, said blades being pressed together when assembled in the timer to assume a substantially straight line position, face to face, the cams having cam surfaces which engage the opposite sides of the arm and positively move it back and forth, a pair of stationary breaker points. mounted independently of said arm and adapted to be contacted alternately by said movable breaker points with lateral movement of the arm, and a dampener for the opposite, non-pivotal end of the arm which prevents lateral swing thereof, but permits lateral displacement of the arm at the movable breaker points.

6. A timer comprising two rotatable cams, an arm disposed between said cams, the arm being pivoted at one end and having a pair of movable breaker points mounted thereon inwardly of its opposite end, said armbeing composed of two elongated, spring-blades which are flared outwardly at the non-pivotal end of the arm, the cams having cam, surfaces which engage the opposite sides of the arm and positively move it back and forth, a pair of stationary breaker points mounted independently of said arm and adapted to be contacted alternately by said movable breaker points with lateral movement of the arm, and a pair of substantially rigid members flanking the arm at its outwardly flared end, the flared ends of the blades pressing against the flanking members under spring pressure and serving to dampen the independent vibratory motion of the arm.

'7. A timer comprising two rotatable cams, an arm having a movable breaker point, the arm being disposed between the cams and having mounted thereon a pair of oppositely-disposed retainer boxes for a pair of riding blocks, the cams having cam surfaces which engage said riding blocks on the opposite sides of the arm to positively move the arm back and forth, the retainer boxes being mounted on said arms by means of hook portions formed on one of said members engaging flanges formed on the other of said members, and a stationary breaker point or points mounted independently of said arm and adapted to be contacted by said movable breaker point with lateral movement of said arm.

8. A timer according to claim 7, in which the hook portions are formed on the retainer boxes, and the flanges are formed on the arms.

9. A timer comprising two rotatable cams, an arm having a movable breaker point, the arm being disposed between the cams and having mounted thereon a pair of oppositely-disposed retainer boxes for a pair of riding blocks, the

cams having cam surfaces which engage said rid ing blocks on the opposite sides of the arm to positively move the arm back and forth, the retainer boxes being mounted on said arm by means of hook portions formed on the top and bottom edges of the boxes which embrace a pair of correspondingly located, outwardly-turned, flanges on said arm, and a stationary breaker point or points mounted independently of said arm and adapted to be contacted by said movable breaker point with lateral movement of said arm.

LEONARD J. ARMSTRONG. 

